bitmap2component: add management of image resolution: Is read from file, when exists, and can be modified in bitmap2component.
It also fix issue #747631

Corrected the error message about required OpenGL version for GAL. Fixed pcb_calculator .desktop file.

Footprint Editor: fix a crash when the dialog to set pad properties is called from the main toolbar (i.e. to define the default setting for new pads, and not to edit an existing pad)

* Fix Python scripting error causing pcbnew_wrap.cxx to fail to build.
* Fix OpenGL canvas ratsnest missing connections in copper zones.

Workarounded SWIG problems (does not support nested C++ classes, more on the subject: http://www.swig.org/Doc1.3/SWIGPlus.html#SWIGPlus_nested_classes).

Rework on 3D viewer (work in progress): Disable or enable layers, grid or 3D footprint shapes should be now faster.

* Make block rotate command honor the rotation angle setting.  Thank you
  Umesh Mohan <mohan.umesh@gmail.com> for the patch.
* Change block rotate undo command from UR_ROTATE to UR_CHANGED so consecutive
  rotations do not lead to round errors and for proper undo in case the user
  changes the rotation angle setting between block rotations.

* Handle different item global deletions correctly.  No more removing of text
  if graphics is selected.
* Layer settings are always obeyed for modules, zones, text, and graphics.
* Text will be removed from copper layers if all layers are selected or
  according to the current layer.
* Added check boxes for "normal" and "locked" footprints to be consistent
  with the naming for the track deletion options.

Commit patch about  cvpcb, pcbnew and layout editor menu items, with 3 menu labels modified in Eeschema.

Fix also other very minor issues.
Realistic mode shows or not the copper thickness (depending on selected option in preferences) to speed up the screen redraw.

Fix for bug #1285878, build fails with clean repository and high parallelism due missing dependance between router and pcbcommon

[MacOSX] Avoid race between cmake -E copy_directory, which triggers a build error when using an high parallelism